Field of the Invention and Related Art Statement
The present invention relates to a data processing apparatus for use in an electronic research system in which data produced at a plurality of terminals is transmitted to a data center which statistically processes the data.
In an electronic data processing apparatus such as an apparatus for deriving television audience ratings data and market research data, stored in a number of terminals are transmitted to a data center by means of communication lines such as telephone links. The data center processes the received data to derive the desired television audience ratings data and market research data. In one of the known data processing apparatuses, the transmission of the data from a terminal to the data center is initiated when a main memory is filled with the data. In the terminal, i.e. the panelist's home, a conventional telephone link is used as the data transmission line, and the data transmission is effected during a given time period called a time gate (TG) around midnight or during the early morning in order not to disturb normal usage of the telephone at the panelist's home. The data transmission is initiated in response to a polling procedure from the data center. In Japanese Patent Publication Kokai Sho 54-101,607, there is disclosed a television audience rating research system utilizing the above mentioned method.
At the terminal, the data is converted into a signal having a given format and is stored in RAM. The data read out of RAM is transmitted to the data center once a day or once a week.
The terminal includes a ROM which stores a program and various kinds of fixed constants as well as the telephone number of the data center, the open and close times of the time gate TG, the data format, etc. The contents stored in ROM may be changed. For instance, the data format may be altered by manually operating dip switches.
If the transmission of data from the terminal to the data center were initiated when the main store in the terminal is filled with the data, the data transmission might occur when the panelist is using the telephone or wants to use the telephone. This might interfere with the data transmission. It might also interfere with normal usage of the panelist's telephone, making it rather difficult to obtain the cooperation of the panelist. If a time gate is set during a low traffic time period such as midnight and early morning, and if the number of terminals is increased, it becomes difficult to complete or finish the data transmission process for all the terminals during only the mid night and early morning period, and again the data transmission might compete with the normal usage of the telephone by the panelist. In order to mitigate such a drawback, the number of telephone links and the size of the computer installed in the data center have to be increased. However, since the utilization rate of the telephone links by the data center is very low, such as about 13%, the cost performance of the data center becomes extremely low.